Reamer-stabilizer

ABSTRACT

A reamer-stabilizer for rotary drilling of earth formations includes a body for transmitting fluid, axial loads, bending moment, and torque, to which fixed, wall contacting blades are replaceably attached by means including body portions suitable also for replaceable attachment of rolling cutters if desired. The wall contacting elements, blades or rollers, are set tangent to a helix concentric with the body. The blade attachment means may include hard resilient antifretting means.

United States Patent Hughes et al.

[151 3,680,646 [4 1 Aug. 1,1972

[54] REAMER-STABILIZER 72 Inventors: Robert Q. Hughes, Midland; William R. Garrett, Houston, both of Tex.

[7 3] Assignee: Smith International, Inc.

[22] Filed: Oct. 28, 1970 21 Appl. No.: 84,726

521 U.S.Cl....., ..'....17s/s2s,17s/32s [51] Int. Cl. ..E21b 17/10 [58] Field of Search ..l75/342, 406, 345-347, 175/323, 325; 308/4 A [56] References Cited UNITED STATES PATENTS 1,932,488 10/1933 Scott ..l75/406 2,088,770 8/1937 Skinner 175/406 2,310,584 2/1943 Kennedy ......175/346 2,657,907 1 H1953 Cochran et a1 .....l7$/406 X 3,052,310 9/1962 Kinzbach 175/406 3,476,196 11/1969 Whittle et al. 175/325 Primary Examiner-David H. Brown Attorney-Murray Robinson and Ned L. Conley [57] ABSTRACT A. reamer-stabilizer for rotary drilling of earth formations includes a body for transmitting fluid, axial loads, bending moment, and torque, to. which fixed, wall contacting blades are replaceably attached by means including body portions suitable also for replaceable attachment of rolling cutters if desired. The wall contacting elements, blades or rollers, are set tangent to a helix concentric with the body. The blade attachmenfmeans may include hard resilient antifretting means.

15 Claim, is Drawing Figures REAMER-STABILIZER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to drilling tools and more particularly to reamer-stabilizers used in the rotary drilling of earth formations such as oil wells.

2. Description of the Prior Art Reamer-stabilizers for rotary drilling of earth formations include a fixed blade type wherein the wall contacting elements are fixed to a tubular body which forms part of the drill string, such body transmitting fluid, torque, axial loads, and bending moment. Such blades may be attached to the body by means enabling replacement when the blades wear out or the size needs to be changed. An example of this type of construction is disclosed in US. Pat. No. 1,937,742 issued Dec. 8, 1933 on the application of M. D. Brink.

Another type of reamer-stabilizer is of the roller type wherein the wall contacting elements, i.e., rollers, are rotatably mounted on shafts attached to the body. The rollers can be replaced when they are worn out. To provide for such replacement the ends of the shafts on which the rollers are mounted may be disposed in blocks releasably held to the reamer body as shown in US. Pat. No. 3,306,381 issued Feb. 28, 1967, on the application of W. R. Garrett et al. The blocks have a life of perhaps 10 times that of the rollers and shafts but can also be replaced when needed.

Reamer-stabilizers in which the wall contacting elements are slanted, i.e., inclined to the body axis in such a manner as to be tangent to a helix concentric with such axis are also known, one form employing roller type wall contacting elements with replaceable blocks for mounting the roller shafts, the assembly being somewhat similar to that used in the construction of said Garrett et al., patent, another form using replaceable fixed blades driven into grooves in the body and retained by lock pins, as in the aforementioned Brink patent.

Certain prior art reamer-stabilizers employing replaceable fixed blades are unsatisfactory for heavy duty because they often fall apart in the earth bore.

SUMMARY OF THE INVENTION According to the invention a replaceable fixed blade reamer-stabilizer is provided which is of greater strength than the aforementioned prior art constructions and hence less apt to break up in the earth bore. The fixed replaceable blades are provided with longitudinal holes whereby they can be mounted on shafts held in blocks removably mounted on the body. Each end of each blade has an end portion overhanging the adjacent block, an inner flat face of such end portion engaging an outer fiat face of the block to prevent rotation of the blade on the shaft. Hard elastomeric material is provided between such faces to prevent fretting, preferably being mounted on the face, e.g., of the block, which has the greater area, to enable mechanical side retention to be employed.

The fixed blade mounting blocks and the fixed blades themselves are constructed to fit portions of the body of the reamer which are also suitable for receiving rollers and different blocks suitable for mounting the rollers. This construction has the added advantage of enabling the body to be dressed with rollers instead of fixed blades whenever rollers are preferred. This option is especially desirable in a reamer-stabilizer employing slanted wall contacting elements since users of such slanted element reamer-stabilizers work in formations where alternation between the two types of wall contacting elements may be frequent.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation showing a fixed, replaceable blade reamer-stabilizer embodying the invention;

FIGS. 2 and 3 are modified sections taken approximately at planes 2-2 and 3-3 of FIG. 1, showing the undressed body of the reamer-stabilizer illustrated in FIG. 1;

FIG. 4 is a fragmentary section through the axis of one of the shafts showing one of the blades and mounting means therefor forming part of the reamer-stabilizer illustrated in FIG. 1;

FIG. 5 is a view taken at plane 5-5 of FIG. 4, showing the blade and blocks, the hard facing of the blade being omitted;

FIGS. 6, 7, and 8 are sections taken at planes 6-6, 7-7, and 8-8 of FIG. 4;

FIGS. 7A and 7B are fragmentary views similar to FIG. 7 showing modifications;

FIG. 9 is an elevation similar to FIG. 1 showing the reamer-stabilizer dressed with roller type wall contacting means;

FIG. 10 is a view taken at plane 5-5 of FIG. 4, but showing only the body of the reamer-stabilizer;

FIG. 1 1 is view similar to FIG. 4 but to a smaller scale and showing the reamer-stabilizer dressed with roller type wall contacting means.

The construction shown in FIGS. 9-1 1 represents the prior design made by applicants assignee upon which the present invention is an improvement.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIG. 1 there is shown a reamer-stabilizer 11 including a generally cylindrical tubular steel body 13 having means at each end for making connection with other drill string members, e.g., a threaded pin 15 at the upper end for making connection with a drill collar and a threaded box 17 at the lower end for making connection with a drill bit.

Referring now also to FIGS. 2 and 3, there is a flow passage 19 extending axially through body 11 and equiazimuthally spaced apart around the body 11 are a plurality of recesses 21. The recesses have semicylin drical bottom portions and parallel planar side walls at their mouths. The axes of the recesses are inclined so as to be tangent to helixes concentric with the axis of body 13.

Adjacent the upper and lower ends of each recess 21 are generally rectangular channels 25, 27. Referring now also to FIGS. 4-8, and 10, within channels 25, 27, are received upper and lower generally rectangular blocks 29, 31. There are keys 33 in upper channels 25 and keys 35 in lower channels 27, the keys being parallel to the axes of recesses 21 and equidistant from the axis of the body. The upper blocks are provided with keyways 37 adapted to engage keys 33, and the lower blocks are provided with similar keyways 39 adapted to engage keys 35. Preferably the upper and lower blocks make interference fits with the upper and lower channels'at the sides thereof. The inner faces of the blocks and the adjacent portions of the channels are rounded at their edges, as shownat 41, 42, 43, 44. The inner faces of the blocks and the adjacent inner faces of the channels may also makean interference fit. The blocks may be driven into the channels from'the recesses 21. The lower ends of the lower blocks are rounded at their corners 45 and abut against shoulders 46 where the lower channels join lower rectangular grooves 47. The upper ends of the upper blocks are rounded at their corners 49 and abut against shoulders 51 where the upper channels join upper rectangular grooves 53.

The upper and lower blocks are provided respectively with openings 55, 57. Slidably received at their upper and lower'ends in the openings 55, 57 are shafts 59, of which there are three: Preferably. the shafts 59 do not make interference fits with the openings 55, 57. To retain each shaft against axial displacement and incidentally to prevent its rotation, each shaft is provided, tag, at itsupper'end, with a transverse passage,

e.g., a groove 61 which slidably receives a roll pin 63.

, jacent the upper end of each shaft there is a safety lock screw 71 screwed into a hole 72 in groove 53 in body 13', so that the shaft cannot move out axially upwardly.

Groove 53 provides a passage enabling shafi 59 to be inserted through openings 55, 57 after the blocks 29, 31 have been driven into place. A short relief passage 70 at the lower end of each groove 47 facilitates entrance of a tool to push shaft 59 out through groove 53 when it is desired to redress the reamer-stabilizer.

Mounted on each 'shaft59 is a wall contacting element in the form of a fixed blade 73. Each blade 73 includes a body 74 of generally rectangular cross section havingone curved cylindrical side forming the outer face of the blade, the cylinder axis being the longitudinal or flow axis of body 10. Each blade is provided with a longitudinalaperture 75 through which slidably extends the shaft 59. The length of each body 74 is such as to fit snugly between blocks 29, 31. Each blade 73 is provided at its upper and lower ends with tips 77, 79

which overlie blocks 29, 31, the inner faces 81, 83 of the tips being flat and correlative to the flat outer faces of wear inserts 85, 87 set in the outer faces of the blocks, thereby providing means to prevent rotation of the blade on the shaft.

To the cylindrical outer face 89 of each blade is welded a hard facing material 91 such as tungsten carbide. The hard facing extends out over the tips 77, 79

and the bevels 93, 95 at the extremities thereof. It is to be noted that the bevels 93, 95 are at right angles to the axis of the body of the tool and hence slant at angles other than right angles relative to the lengths of the blades 73.

, Referring once again to the wear inserts 85, 87, these are to prevent fretting which might occur if the tips of the blades were allowed to engage the, metal blocks 29,

31. However, if the manufacturing tolerances are maintained close enough to prevent much relative motion of the blade and blocks, the wear inserts maybeomitted and direct metal to metal contact of the blades and books allowed, e.g., as shown at 81, 97 in FIG. 7A.

If wear inserts 85, 87 are employed, they are preferably made of a hard elastic material such as a synthetic rubber or other elastomer having a durometer hardness between 0 and 100 on the Shore fD" or a durometer hardness between '50 and 100 on' the Shore A scale but incorporating a harder reinforcement such as fabric. Such a fabric reinforced wear insertisillustratedat99inFIG.713.

Although the wear inserts need only be between the blades and the blocks, the wear inserts are preferably placed in the faces of the blocks rather than the faces ofthe blade tips because the block faces are of larger area than the blade tip faces. enablesthe wear inserts to cover the entire engaged surface and also to bemechanically supported attheir side edges,

e.g., by the sides 101, 103 of therecesses 105 in the If desired the previously described fixed blade reamer-stabilizer can be dressed with rollers as shown in FIGS. 9 and 11. Except for the fact that the rollers are inclined 12 relative to the body axis, the construetion is substantiallythe same as in the aforementioned Garrett etal patent. Briefly the arrangement includes blocks 111, 112, shaft 113, roller type wall contacting elements 115, and roll pin 117. A tab 119 on the lower:

end of the shaft fits in a slot 121 in the lower block 1 11.

Rotation of the shaft is thus'prevented independently of pin 117. It will be noted that the blocks 111, 112 are somewhat deeper (radial extent relation t'o'the body) than those used for dressing the reamer-stabilizer with fixed blades, with the result that each shaft 113 is displaced radially outwardly as needed to accommodatethe rollers 115 within recesses 21. An incidental result is that the transverse passage 119' in shaft 113 which receives pin 117 is a cylindrical hole rather than a groove. It is, of course, desirable-to keep pin 117 as near ,to the surface of the body as possible to prevent weakening of the body.

Whenever'desired it is an easy matter to remove screw 71, drive out pin 117 and remove shaft 113 and roller 1 15, following which the worn roller and/or shaft can be replaced. The blocks can also be replaced if worn out. If it is desired to convert to fixed blade dress,

the blocks 1 11, 1 12 can also be driven out and replaced with blocks 29, 31. Then a blade 73 is positioned between each pair of blocks 29, 31 and a shaft 59 slipped therethrough and locked in place with pin 63 and screw 71. The fixed blade reamer-stabilizer of FIG. 1 is then recreated. If the fixed blades wear out, they can be replaced by removing screw 71, driving out pin 63, and removing shaft 59 and blades 73, following which the worn blades can be replaced. The shafts and blocks can also be replaced if worn out. Also, the blocks, shafts and blades can be replaced with roller dress whenever desired.

Although the wall contacting elements, blades or rollers, have been described as being set at an angle, e.g., 12, to the body axis, and as being tangent to a helix concentric with such body axis, the invention is applicable to other settings of the wall contacting elements, for example, with their axes parallel to the body axis or lying on elements of cones concentric with the body.

While a preferred embodiment of the invention has been shown and described, modifications thereof can I be made by one skilled in the art without departing from the spirit of the invention.

We claim:

1. Drilling tool comprising:

a tubular body having a flow passage therethrough and means at its ends for making connection with other drill string members,

a recess in said body disposed at the periphery thereof and adapted to receive a wall contacting element,

a wall contacting element received in said recess and protruding radially outward therefrom,

said wall contacting element having an aperture ex tending therethrough from the end of the element nearest one end of the body to the end of the ele' ment nearest the other end of the body,

a shaft extending through said aperture,

means releasably mounting the ends of said shaft to said body, and

antirotation means preventing rotation of said wall contacting element on said shaft.

2. Tool according to claim 1 wherein the axis of said shaft is tangent to a helix concentric with the flow axis of said body, said wall contacting element having an outer face that is cylindrically curved about said flow axis.

3. Tool according to claim 1 wherein said antirotation means includes a portion with which said element is provided extending over the edge of said recess engaging cooperative means with which the body is provided.

4. Tool according to claim 3 wherein the surface of said extending portion of the blade is flat where it engages said cooperative means and said cooperative means includes a flat surface where it engages said extending portion.

5. Tool according to claim 3 including antifretting means between said extending portion of said wall contacting element and said cooperative means with which the body is provided.

6. Tool according to claim 5 wherein said antifretting means comprises a wear insert of elastic material having a Shore Durometer hardness of greater than 0 and less than on the D scale.

7. Tool according to claim 5 wherein said antifretting means comprises a wear insert of elastic material having a Shore Durometer hardness of greater than 50 and less than 100 on the Shore A scale, said material being reinforced with fabric.

8. Tool according to claim 1 wherein the means releasably mounting the shaft to the body includes a mem r teachen ofte h t avin a aert re into w lci l extends t e en of tii s aft, %:ac ii r em er being releasably mounted on the body, the wall contacting element engaging said members at its ends to prevent axial motion of the wall contacting element on the shaft. 7

9. Tool according to claim 8, each of said members being a block fitted in a channel in said body having a stop shoulder at one end and connecting at its other end with said recess and including means retaining said blocks in said channels against outward displacement and means preventing axial movement of said shaft in said blocks comprising a pin entending transversely through one of said blocks and a groove in the shaft opening toward the outside of said body.

10. Tool according to claim 8, wherein the antirotation means includes a portion with which said element is provided extending over the edge of the recess and cooperating means with which one of the shaft mounting members carried by the body is provided.

11. Tool according to claim 10 including antifretting means between the adjacent surfaces of said extending portion of the wall contacting element and said shaft mounting member.

12. Tool according to claim 11 wherein the antifretting means comprises an elastomer vulcanized to one of said adjacent surfaces.

13. Tool according to claim 11 wherein said antifretting means comprises a wear insert set in a recess in one of the adjacent surfaces between which is set th antifretting means. i

14. Tool according to claim 13 wherein the wear insert is set in a recess in said surface of said shaft mounting member and extends laterally beyond said extending portion of said wall contacting element.

15. Tool according to claim 14 wherein said wear insert is cemented in said recess. 

1. Drilling tool comprising: a tubular body having a flow passage therethrough and means at its ends for making connection with other drill string members, a recess in said body disposed at the periphery thereof and adapted to receive a wall contacting element, a wall contacting element received in said recess and protruding radially outward therefrom, said wall contacting element having an aperture extending therethrough from the end of the element nearest one end of the body to the end of the element nearest the other end of the body, a shaft extending through said aperture, means releasably mounting the ends of said shaft to said body, and antirotation means preventing rotation of said wall contacting element on said shafT.
 2. Tool according to claim 1 wherein the axis of said shaft is tangent to a helix concentric with the flow axis of said body, said wall contacting element having an outer face that is cylindrically curved about said flow axis.
 3. Tool according to claim 1 wherein said antirotation means includes a portion with which said element is provided extending over the edge of said recess engaging cooperative means with which the body is provided.
 4. Tool according to claim 3 wherein the surface of said extending portion of the blade is flat where it engages said cooperative means and said cooperative means includes a flat surface where it engages said extending portion.
 5. Tool according to claim 3 including antifretting means between said extending portion of said wall contacting element and said cooperative means with which the body is provided.
 6. Tool according to claim 5 wherein said antifretting means comprises a wear insert of elastic material having a Shore Durometer hardness of greater than 0 and less than 100 on the ''''D'''' scale.
 7. Tool according to claim 5 wherein said antifretting means comprises a wear insert of elastic material having a Shore Durometer hardness of greater than 50 and less than 100 on the Shore ''''A'''' scale, said material being reinforced with fabric.
 8. Tool according to claim 1 wherein the means releasably mounting the shaft to the body includes a member at each end of the shaft having an aperture into which extends the end of the shaft, each member being releasably mounted on the body, the wall contacting element engaging said members at its ends to prevent axial motion of the wall contacting element on the shaft.
 9. Tool according to claim 8, each of said members being a block fitted in a channel in said body having a stop shoulder at one end and connecting at its other end with said recess and including means retaining said blocks in said channels against outward displacement and means preventing axial movement of said shaft in said blocks comprising a pin entending transversely through one of said blocks and a groove in the shaft opening toward the outside of said body.
 10. Tool according to claim 8, wherein the antirotation means includes a portion with which said element is provided extending over the edge of the recess and cooperating means with which one of the shaft mounting members carried by the body is provided.
 11. Tool according to claim 10 including antifretting means between the adjacent surfaces of said extending portion of the wall contacting element and said shaft mounting member.
 12. Tool according to claim 11 wherein the antifretting means comprises an elastomer vulcanized to one of said adjacent surfaces.
 13. Tool according to claim 11 wherein said antifretting means comprises a wear insert set in a recess in one of the adjacent surfaces between which is set the antifretting means.
 14. Tool according to claim 13 wherein the wear insert is set in a recess in said surface of said shaft mounting member and extends laterally beyond said extending portion of said wall contacting element.
 15. Tool according to claim 14 wherein said wear insert is cemented in said recess. 